CF1099B.Squares and Segments

Little Sofia is in fourth grade. Today in the geometry lesson she learned about segments and squares. On the way home, she decided to draw $n$ squares in the snow with a side length of $1$. For simplicity, we assume that Sofia lives on a plane and can draw only segments of length $1$, parallel to the coordinate axes, with vertices at integer points.

In order to draw a segment, Sofia proceeds as follows. If she wants to draw a vertical segment with the coordinates of the ends $(x, y)$ and $(x, y+1)$. Then Sofia looks if there is already a drawn segment with the coordinates of the ends $(x', y)$ and $(x', y+1)$ for some $x'$. If such a segment exists, then Sofia quickly draws a new segment, using the old one as a guideline. If there is no such segment, then Sofia has to take a ruler and measure a new segment for a long time. Same thing happens when Sofia wants to draw a horizontal segment, but only now she checks for the existence of a segment with the same coordinates $x$, $x+1$ and the differing coordinate $y$.

For example, if Sofia needs to draw one square, she will have to draw two segments using a ruler:

After that, she can draw the remaining two segments, using the first two as a guide:

If Sofia needs to draw two squares, she will have to draw three segments using a ruler:

After that, she can draw the remaining four segments, using the first three as a guide:

Sofia is in a hurry, so she wants to minimize the number of segments that she will have to draw with a ruler without a guide. Help her find this minimum number.

小索菲亚上小学四年级。今天在几何课上，她学习了线段和正方形的概念。放学回家的路上，她决定在雪地上画 $n$ 个边长为 $1$ 的正方形。为简化问题，我们假设索菲亚生活在一个平面上，且只能画出长度为 $1$、平行于坐标轴的线段，且所有端点均为整数坐标点。

索菲亚画一条线段的过程如下：若她想画一条竖直线段，其两个端点坐标为 $(x, y)$ 和 $(x, y+1)$，则她会先检查是否已存在某条竖直线段，其两个端点坐标为 $(x', y)$ 和 $(x', y+1)$（其中 $x'$ 为某个整数）。若存在这样的线段，则索菲亚可快速画出新线段，并以该已有线段为参照；否则，她必须借助直尺仔细测量，耗时较长。类似地，当她想画一条水平线段（端点为 $(x, y)$ 和 $(x+1, y)$）时，她会检查是否存在另一条水平线段，其两个端点具有相同的 $x$、$x+1$ 坐标，而 $y$ 坐标不同（即是否已存在某条水平线段 $(x, y')$ 和 $(x+1, y')$）。

例如，若索菲亚需画一个正方形，则她必须用直尺画出两条线段：

之后，她便可利用这两条已画好的线段作为参照，画出剩余的两条线段：

若索菲亚需画两个正方形，则她必须用直尺画出三条线段：

之后，她便可利用这三条已画好的线段作为参照，画出剩余的四条线段：

索菲亚赶时间，因此希望最小化必须用直尺（无参照）绘制的线段数量。请帮她找出这个最小数量。

The only line of input contains a single integer $n$ ($1 \le n \le 10^{9}$), the number of squares that Sofia wants to draw.

输入仅包含一行，其中有一个整数 $n$（$1 \le n \le 10^{9}$），表示索菲亚想要绘制的正方形数量。

Print single integer, the minimum number of segments that Sofia will have to draw with a ruler without a guide in order to draw $n$ squares in the manner described above.

输出一个整数，即索菲亚按照上述方式画出 $n$ 个正方形时，必须用直尺（无辅助线）绘制的最少线段数量。